The death of veteran Fox Lake, Illinois, police officer Lt. Joseph Gliniewicz was a "carefully staged suicide," investigators said Wednesday.

"We have determined this staged suicide was the end result of extensive criminal acts Gliniewicz had been committing and the fact he was under increasing levels of personal stress from scrutiny of his management of the Fox Lake Police Explorer program," said Lake County Major Crimes Task Force Commander George Filenko.

Filenko claimed Gliniewicz had been stealing and laundering money from the Fox Lake Police Explorer Post, a program that instructs youth between the ages of 14 and 21 on law enforcement material, over the past seven years. He said Gliniewicz used thousands of dollars for personal purchases, mortgages, travel expenses, gym memberships, adult websites and to facilitate personal loans. He also said Gliniewicz forged signatures in official documents.

Gliniewicz also made incriminating statements in text messages that were deleted prior to his suicide, Filenko said, adding that Gliniewicz appeared stressed about being discovered and felt "as if everything has come to a close, so to speak, surrounding him."

Lieutenant's Suicide Was 'Ultimate Betrayal': Officials

Lake County Major Crimes Task Force Commander George Filenko said in a press conference Wednesday that the death of veteran Fox Lake police officer Lt. Joseph Gliniewicz in September was a "carefully staged suicide," adding that it was the "ultimate betrayal." (Published Wednesday, Nov. 4, 2015)

Among the messages are statements from Gliniewicz claiming he used money from the Explorer account to pay for a $624.70 flight. Another one claims that if the Fox Lake village administrator "gets ahold of the checking account I'm pretty well [expletive]."

"There are no winners here," Filenko said. "Gliniewicz committed the ultimate betrayal to the citizens he served and the entire law enforcement community."

The investigation also "strongly indicates criminal activity" from at least two other people, Filenko said, but he declined to comment further as an investigation into that claim is ongoing.

Commander: First Time I've Felt 'Ashamed' of Another Officer

Lake County Major Crimes Task Force Commander George Filenko said Wednesday that Lt. Joseph Gliniewicz's "staged suicide" was the first time in his career that he has "felt ashamed of another police officer." (Published Wednesday, Nov. 4, 2015)

"While some wanted the results fast, we wanted them right," said Detective Christopher Covelli with the Lake County Sheriff's office. "We were obligated to prove our conclusions before we reported to you and the public we serve."

Covelli said more than 430 leads were examined in the investigation along with 250 pieces of evidence, 6,500 pages of text messages from Gliniewicz's phone and 40,000 emails.

Officials said pepper spray, a baton and Gliniewicz's personal glasses were strategically placed around the scene as "an attempt to lead investigators to believe this was a homicide scene." They added that Gliniewicz had "significant experience" staging mock crime scenes for police explorer training.

Lieutenant's Crimes Would Have Been Discovered 'Eventually'

Lake County Major Crimes Task Force Commander George Filenko said in a press conference Wednesday that Lt. Joseph Gliniewicz's criminal acts would have been discovered "eventually," even if there had not been an investigation into his death. (Published Wednesday, Nov. 4, 2015)

"This was laid out to seem as if there was an ongoing type of struggle through the scene," he said.

In addition, the first of two gunshots was "strategically aimed" so that it hit his cell phone and bulletproof vest.

The conclusion is a shocking end to months-long mystery surrounding the veteran officer's death.

"The embarrassment comes to me personally that this is the first time, in my career, that I’ve felt ashamed by the acts of another police officer," Filenko said.

Messages Shed Light on Lieutenant's Criminal Activity: Officials

A series of text and Facebook messages indicating Lt. Joseph Gliniewicz was under stress, possibly due to his criminal activity, was recovered during the investigation into his death, Lake County Major Crimes Task Force Commander George Filenko said. (Published Wednesday, Nov. 4, 2015)

Gliniewicz, a married father of four, was last heard from the morning of Sept. 1 when he called for backup while on duty, reporting on his radio he was pursuing three suspicious men in a remote area of the village just south of the Wisconsin state line.

Just 17 minutes later, the responding backup officers found him dead, fatally shot twice with his own gun. One of the shots entered the right side of the front of the officer's vest. Another was fired in the upper chest region.

His death rocked the country and sparked a furious search for the suspects — who Gliniewicz had described as two white men and one black man — involving more than 400 officers, helicopters and canines. The investigation has reportedly cost more than $300,000, but police never made any arrests, identified any suspects or established a motive.

"We completely believed from day one that this was a homicide," Filenko said, adding that the criminal activity was discovered later in the investigation.

Officials Expected to Declare Officer's Death a Suicide

At a Wednesday press conference investigators are expected to announce that they believe veteran Fox Lake police officer Lieutenant Joseph Gliniewicz committed suicide, according to a law enforcement official familiar with the findings. NBC 5's Natalie Martinez reports. (Published Wednesday, Nov. 4, 2015)

In the Wednesday announcement, officials revealed that there were no signs Gliniewicz had been dragged after being shot and there were no physical signs that he fought for his life. They added that his weapon hadn't been found at the scene until nearly two hours after his death.

"We explored every possibility of what could have happened out there," Filenko said.

The 52-year-old officer was on the cusp of retirement before his death. He left behind a wife of 30 years, Melodie, and four sons. Throughout the drawn-out investigation, the lieutenant's family firmly stood against swirling rumors that Gliniewicz may have taken his own life.

Manhunt, Lockdown Continues in Fox Lake

SUICIDE PREVENTION: The National Suicide Prevention Hotline (1-800-273-8255) is open 24 hours a day, 7 days a week.